Flow meter



retenus-Api. 21, 193s lPai* aosasiif f y' -ziiasli Y .FLOW Mama w AFelix munsaantubmmmr., .enigmi-@Snell Development Company, SanFrancisco,:,Calif..` ',-1

invention. is particularlyeoncerned with a metering 'F'device'ffor liquids under prese- Vsurefequal to their vapor pressure. f

Recently ammonia yhas been added toirriga# l 5 tion waters for the purpose of-fertilizing growing crops.l Now order 'toinsure a determined amount of fertilizer being delivered to each tree l or plant with a. given owit is knecessary that v means be provided for gauging and regulating the l rate of delivery of the ammonia to the water f The usual practice is tov convey thelammoniato the place ofapplicationgasrliquid.anhydrous am'- vmania in suitable pressure-cylinders.

liiiristing-v meteringgandjdistributing devices yfor i theammonia atthe necessary low rates of feed consist inthe of a pressurereducing and l`control valve, yaufevaporatingcoil for the ammonia and afgas delivery lpipe extending to ay 'point 'below lthe level 'of the water in 'the irriga- 2'0- tion ditch.- A .p'ressure gauge consisting of a U tube is connected to the outlet end of the evaporating coil by'a suitable T. The now of ammonia is regulated by adjustment of the pressure reducing valve to produce a previously ascertained'pressure at the outlet end of the evaporating coil corresponding to the desired rate of feed.

The above type of meter proves unsatisfactory for several. reasons. 'For example-the source A A of heat supply necessary in/order to` insure the ready evaporation of the ammonia is not always readily available; the apparatus is somewhat delicate requiring very careful handling; and the rate of delivery often varies irrespectiveV of the pressure `registered on the gauge. due, ,for example, to the lowering 'or raising ofthe level of water. in the irrigation ditch. t i

It is therefore an object of my invention' to devise a meter which will be free from the above defects.-

. 4 The furtherobjectsand advantagesof inyin-4 vention will be apparent from the following description of a specific embodiment hereinafter described ywith. referenceV to the accor'ripanyir'igr drawing of which. Fig. I is an elevation of the y'y metering devicepartly'in section. Fig. II is a general elevation showing how the `meteris s, utilized. Fig. IIIshows a planview of manifolding ofcylinders. e

tion between the two flanges (2) and (I). V'llhe 55 outaend or the tuberi) is nues with; aange 1) ,to wmcnis attached an en'd plate (si bybolts (n ,i The end i piste m is nid lwith a snort inletpipe (i0), of, substantially less diameter than the tube (i). To the outerl end of tube (2) a regulating valve,(ll) is attached., Towards the 5 outer ends of theitubesu) and (2)` two-thermometer wells-02) .and (Il) are provided. y'Ihe whole meter isencasedin=suitable readily :removl ablexinsulation (Il) which is preferably hinged along the longitudinal axis of the meter'.

wells ('I2) "an d (il) whenlthe meteris in'use.y t* The operation-'ofthe `meter can bes'tbe ezt-` with reference ltoa specific useto which the meter placed i. e. themetering of l5 ammonia intoa flowingstream of irrigation wa.

ter. vA typical arrangement'of `thefa'pparati-iskk isV shown yin Iilg.l II. "A cylinder of. liquidanhydrous ammonia f(l'|) fitted .with an internal tubej(il) is supported in the `position shown by 20- means of ablocl: of wood (ISL-so that ammonia can be continuously withdrawn from the cylinder in the liquid anhydrous-state. The cylinder (Il) is provided with a shut-oifvalve (2|),5the discharge yside of kwhich' is .connected by suitable 25 tubing (2|).tothe short'inletfpipe (il) of the meter. An oriceplate (l) having anoriflce `of such size thatit will permit sumcient liquid anhydrous `ammonia to pass through in order to supply therequired amount of ammonia to the 30 stream of irrigation water is clamped between the flanges (3) and (4) with itsflat face towards the ammonia cylinder. A length of pipe (22) extending into the water of the irrigation (2l) is connected to the discharge sideofregulating valve 36 (I I) by the usual pipe connections. Thin oil or other suitable liquid is placed in the thermometer after the' air in the meter-has been displaced.- The meter will now be full ofliquid anhydrous' ammonia. .'lheteniperatureof the-ammonia as registered on tneinermometer (Il) near theiniet v end of the meter'is noted.

.Having decided upon the me at which ammonia isto begfed intothefirrigation water, a

table previously prepared is consulted from which thetemperature thatwill be produced on the ,thermometer It) with vsuch rate of feed, Vpar-,-

ticular orifice and temperature of thek liquid anhydrous ammonia canbe ascertained;

For example, ina particular meter of thedesign shown inthedrawing with an orincepia 5l Two 1ov thermometers .(IS') and (ii) are placed in the registered upon the thermometer (I6) at the desired rate of. lflow theregulating valve (Il) is opened until such temperature is actually registered onI thermometer (I6). in mind that the to adjust itself.

The above meter may` of course be used to are connected to a manifold (2l), the meter in turn being connected tothe outlet pipe (25) ofthe manifold.

Besides metering ammonia into 4an irrigation ditch the ammonia may be discharged through a suitable connection into water lines under pres'- sure or into thestandpipes or weir boxes which often form a part of an irrigation system. Where discharging into water lines under pressure it is of course necessary that the vapor pressure `of the ammonia at the existing temperature be higher than the pressure in the water line, in order for the meter to operate. l

The meter is based upon the principle that when a liquid such as anhydrous ammonia stored at a pressure equal tothe vapor pressure of the liquid is passed through'a small orice a drop in temperature takes place.v It should be noted that lthe lower theA initial temperature of the liquid anhydrous ammonia the higher the temperature drop will be for a given rate of now.

While I have described my metering device i with respect te the metering oriiq'uid anhydrous It should be borne meter takes a minute or two ammonia 1t should be understood that the metering device could be readily employed formeter-v ing other liqueed gases such as for example, propane or butane.

My meter is especially useful i'orl the metering of small rates of flow. .For example, ammonia deliveries at flow rates within thedllgl 0i' 12 lbs. to 170 lbs. per hour have been made.

I claim as my invention: 1. Apparatus' for metering liquid anhydrous ammonia into water comprising la pressure vessel containing liquid anhydrous ammonia, a conduit leading from said vessel into water, an orice plate traversely Vmounted in said conduit, thermometers in the wall of said conduit on each side of said orifice plate and a regulating valve in l said conduit on the discharge side ofv said orificeand at a point further therefrom than the thermometer on said discharge side.

2. A device for metering flow of liquid anhydrous ammonia comprising a jointed conduit, an orifice plate mounted traversely in `said conduit at said joint, thermometer wells extending into said conduit on each side of said joint, a flanged inletpiece at one end of said conduit, a regulating valve at the outlet end of said conduit and insulation surrounding said conduit substantially as described. f' y 3. Apparatus` for metering liquid anhydrous ammonia into water comprising a pressure vessel containing liquid anhydrous ammonia, a conduit leading from said vessel `into water, van orifice plate -traversely mounted in said conduit and thermometers in the wall of said conduit on each side of said orifice plate, the rate of iiow of said ammonia being determined by the .difference between the indications of said thermometers.

FELIX KORTLANDT. 

